To be honest, I can see reasoning as to why a lot of older fans, who watched the anime as a child, wouldn't be too fond of either re-watching the older series or following the newer ones. However, this thread has been filled with negativity. I just want to shed some light on the subject.
I don't watch the anime religiously, not in the slightest. I've only seen a total of one or two episodes from the fourth generation of the anime. Fair enough, there might not be the most technical storylines within the anime and for the most part it can be repetitive -- but so to are the games. Just because the games are repetitive, doesn't mean I'll stop buying or playing them, because I love Pokemon for what it is.
I'll rewatch the anime for nostalgia reasons, but more importantly, because I love Pokemon and I don't see that ever changing -- so what, I might be a little too old for watching the anime, but I still get enjoyment out of reliving moments from my childhood by watching it. As for the movies, they always have a good storyline behind them, and where as I can't defend the anime series for having good storyline, I can defend the movies. They are what I'd watch the most, because I can enjoy them, even at my age, for the concept and original stories behind each of them.
The point? Really, maybe it is aimed at kids, but isn't the entire Pokemon franchise? Just because it can childish for the most part, I get over it, and enjoy it for what it is. Pokemon. What we all love and why we are all here.